#include<iostream>
#include<fstream>
using namespace std;

long int g,ji[190];
char b[3001],a[3000001];

bool pan()
{
	int i;
	for(i=0;i<g;i++)
	    if(ji[int(b[i])]!=0)
			return false;
	return true;
}

int main()
{
	ifstream fin("writing.in");
	ofstream fout("writing.out");
	long int n;
	int i;
	fin>>g>>n>>b>>a;
	for(i=0;i<190;i++) ji[i]=0;
	for(i=0;i<g;i++)
		ji[int(b[i])]++;
	
	bool p=true;
	int head=0,tail=g-1,k=0;
	
	for(i=head;i<=tail;i++)
		ji[int(a[i])]--;
	p=pan();
	if(p) k++;
	do
	{
		p=true;
		tail++;
		ji[int(a[head])]++;
		ji[int(a[tail])]--;
		p=pan();
		if(p) k++;
		head++;
	}
	while(tail!=n-1);
	fout<<k<<endl;
	return 0;
}